1. Field of the Invention
This invention relates to a method and apparatus for the stressless rolling of metals in a continuous mill train.
2. Description of the Prior Art
During the rolling of elongated products (round iron, shaped sections, rails, girders) in continuous rolling mill trains, where the product is simultaneously held in several rolling stands, the presence of a tractive force (tensive or compressive) between the stands causes distortions to occur in the required profile, and should consequently be minimized or, better still, completely eliminated.
In the case of roughing mill trains, a certain tension is maintained, which is held approximately constant by giving the drive motors an intentionally falling speed-torque characteristic.
The occurrence of tension in finishing mill trains can be prevented by allowing the product to form a loop between stands, and by regulating the speed of each stand, adjusting the height of the corresponding loop.
These procedures, however, are not entirely satisfactory because they cannot be applied with the same success to all types of product.